1. Field of the Invention
The present invention relates to a tension spring device of the kind comprising a length of a draw member, preferably a length of chain consisting of connected links, and a spring element consisting of an elastic material, for example rubber, for imparting elastic properties to the draw member.
2. Description of the Prior Art
In several cases it is desirable to impart elastic properties to a draw member, especially a chain length. Thus, it is often desirable to combine the great tensile strength of the chain with elastic properties. For example when chains are used for the mooring of buoys, towing, anchoring of loads and other anchoring purposes it is advantageous to use an elastic chain length.
Of course it is possible to connect a chain length with any type of a conventional metal spring but for many reasons it is more advantageous to combine the chain length with an elastic material for providing a tension spring device. Thus, it is previously known to vulcanize a chain length into an elastic material, for example rubber, the spring action being provided for example by the fact that the links of the chain are during the vulcanization in a contracted position or by providing the links along a path deviating from a straight line.
The tension spring device of the kind described above, i.e. a chain length vulcanized into an elastic material, has good elastic properties and is also advantageous from other points of view. However, it is a drawback that such a tension spring device cannot be manufactured in any other place than in a factory and especially that a tension spring device of this kind is expensive and difficult to manufacture.